382 



NOTES. 



4 This twofold division is arbitrary. No essential distinction, founded on 

 the nature of the elements concerned, or the laws of their combination, can 

 be made ; and so many so-called organic substances, as urea, ammonia, alco- 

 hol, tartaric and oxalic acids, alizarine, and glucose, have been prepared by 

 inorganic methods, that the boundary-line is daily becoming fainter, and may 

 in time vanish altogether. We would here utter our protest against the in- 

 troduction of any more terms like inorganic, invertebrate, acephalous, etc., 

 which express no qualities. 



5 Even the works of nearly all animals proceed in curves. 



6 London Quarterly Review, January, 1869, p. 142. It is true of any great 

 primary group of animals, as of a tree, that it is much more easy to define 

 the summit than the base. 



7 De Bary on " Myxomycetae ;" Darwin on 44 Carnivorous Plants." 



8 " There are certain phenomena, even among the higher plants, connected 

 with the habits of climbing plants and with the functions of fertilization, 

 which it is very difficult to explain without admitting some low form of a 

 general harmonizing and regulating function, comparable to such an obscure 

 manifestation of reflex nervous action as we have in Sponges and in other 

 animals in which a distinct nervous system is absent. 7 ' — -Prof. Wtville 

 Thomson's Introductory Lecture at Edinburgh. 



9 "If nature had endowed us with microscopic powers of vision, and the 

 integuments of plants had been rendered perfectly transparent to our eyes, 

 the vegetable world would present a very different aspect from the apparent 

 immobility and repose in which it is now manifested to our senses." — Hum- 

 boldt's Cosmos, i., 341. 



10 See Gray's 44 Structural Botany," p. 350 ; Eolleston's "Forms of Ani- 

 mal Life," p. 143. 



11 4 'Life has been called the vital force, and it has been suggested that it 

 may be found to belong to the same category as the convertible forces, heat 

 and light. Life seems, however, to be more a property of matter in a certain 

 state of combination than a force. It does no work, in the ordinary sense." 

 —Prof. Wyville Thomson. 



12 There was a time in our history when a single membrane discharged 

 all the functions of life — digesting, respiring, secreting. The separation 

 of a heart, lung, stomach, liver, etc., for special duty was an after-considera- 

 tion. 



13 The vegetable cell has usually two concentric coverings : cell-wall and 

 primordial utricle. In animal cells the former is wanting, the membrane 

 representing the utricle. As a general fact, animal cells are smaller than 

 vegetable cells. 



14 Cells are not the sources of life, as once thought, but are the products 

 of protoplasm. 44 They are no more the producers of vital phenomena than 

 the shells scattered in orderly lines along the sea-beach are the instruments 

 by which the gravitation - force of the moon acts upon the ocean. Like 

 these, the cells mark only where the vital tides have been and how they 

 have acted." — Prof. Huxley. 



15 Many of the bones of the skull are preceded by membrane — hence called 

 membrane-bones. 



